Azo dyestuffs and process of making the same



Patented Aug. 16, 1932 UNITED STATES PATENT OFFICE, d

GERALD BONHGTE, 0F BASEL, SWITZERLAND, ASSIGNOR TO THE FIRM SOCIETY OECHEMICAL INDUSTRY IN BASLE, OF BASEL, SWITZERLAND AZO DYESTUFFS Annriioonss or MAKING THE SAME No Drawing. Application filed October 24,1931, Serial No. 570,982, and in Switzerland November 15, 1930.

According to this invention a new azo-dyestuff is made by coupling 2:3-hydroxynaphthoic acid-para-anisidide with diazotized 4- chloro 2aminodiphenyl-ether. This dyestufl', which thus corresponds to theformula is a red powder insoluble in water. When produced on the fiberor on a suitable substratum it yields a full red tint of remarkablefastness to light which essentially exceeds that of the hithertodescribed dyestuffs from arylides of 2: 3-hydroxynaphthoic acid anddiazotized o-aminodiaryl ethers. V

The following examples illustrate the invention:

Example 1 29.3 parts by weight of 2: 3-hydroxynaphthoicacid-para-anisidide are dissolved in 500 parts of water withaid of 4parts of caustic soda. 20 parts of calcined sodium carbonate are nowadded and the whole is mixed with a diazo-solution prepared from 22.9parts of 4-chloro-2-aminodiphenyl-ether. The dyestufi separatesimmediately in the form of a red precipitate.

Example 2 Cotton yarn is impregnated with a grounding liquor made bydissolving 7 grams of para-anisidide of 2: 3 -hydroxynaphthoic acid in300 cc. of hot water with addition of 14: cc. of caustic soda solutionof 30 per cent. strength and .10 cc; of Turkey red oil, the whole beingdiluted to 1 liter. The yarn is then wound oil and developed in asolution neutralized by means of sodium acetate containing 4 grams ofdiazotized 4-chloro-2- aminodiphenylether per liter. A red tint isproduced which is of excellent properties of fastness, particularly ofexcellent fastness to light. 1 Fast tints on wool are obtained byWorln'ng as prescribed in British Patent No. 310758.

What I claim is As a new product the azo-dyestufi' of the formula formsa red powder, and, when produced on the fiber, dyes it a full red tintof remarkable fastness to light.

In witness whereof I have hereunto signed my name this 17th day ofOctober, 1931.

GERALD BoNi-Io E.

